PCBC-745: throw BadInputException when string cannot be used as CAS
PCBC-745: throw BadInputException when string cannot be used as CAS

Change-Id: Ie6e31160d64512e697107020daec1b8631d526a4
Reviewed-on: http://review.couchbase.org/c/php-couchbase/+/144274
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Sergey Avseyev <87f6d5e4fd3644c3c20800cde7fd3ad1569370b3@gmail.com>

couchbase/php-couchbase,couchbase/php-couchbase,couchbase/php-couchbase,couchbaselabs/php-couchbase,couchbaselabs/php-couchbase,couchbaselabs/php-couchbase,couchbase/php-couchbase,couchbaselabs/php-couchbase